Image generation system and method

Abstract

An image generation system comprising a bounding volume hierarchy, BVH, storage unit operable to store a BVH comprising a hierarchical structure of a plurality of triangles describing a virtual scene, a BVH position buffer operable to store data for identifying the location of one or more triangles within the BVH, and a fetch shader operable to identify vertex indices for use in rendering images, to obtain one or more triangles within the BVH corresponding to those vertex indices, and to provide vertex data corresponding to those triangles to a vertex shader operable to perform a vertex shading process.

The invention claimed is: 
     
       1. An image generation system comprising:
 a bounding volume hierarchy, BVH, storage unit operable to store a BVH comprising a hierarchical structure of a plurality of triangles describing a virtual scene; 
 a BVH position buffer operable to store data for identifying the location of one or more triangles within the BVH; and 
 a fetch shader operable to identify vertex indices for use in rendering images, to obtain one or more triangles within the BVH corresponding to those vertex indices, and to provide vertex data corresponding to those triangles to a vertex shader operable to perform a vertex shading process, 
 wherein the respective locations of at least some of the plurality of triangles within the BVH are each indicated by a respective index and respective single bit value, which together identify all vertices of a respective one of the at least some of the plurality of triangles. 
 
     
     
       2. The image generation system of  claim 1 , wherein the respective locations of at least some others of the plurality of triangles within the BVH are each indicated by a respective index that identities at least a first vertex, and a respective offset for each other vertex, in a respective one of the at least some others of the plurality of triangles. 
     
     
       3. The image generation system of  claim 1 , comprising a vertex shader operable to perform the vertex shading process using data obtained from the fetch shader. 
     
     
       4. The image generation system of  claim 1 , wherein the vertex shading process comprises one or more of the following:
 modifying a position of a vertex; 
 modifying a colour of a vertex; 
 modifying an orientation of a vertex; and 
 converting a three-dimensional vertex location into a two-dimensional screen position. 
 
     
     
       5. The image generation system of  claim 1 , wherein the fetch shader is operable to perform a transform on the obtained location information for the one or more triangles. 
     
     
       6. The image generation system of  claim 5 , wherein the fetch shader is operable to perform a transform to convert the obtained location information into coordinates in object space. 
     
     
       7. The image generation system of  claim 1 , comprising an index buffer operable to store data identifying vertex indices for use in rendering images. 
     
     
       8. The image generation system of  claim 7 , comprising a vertex buffer operable to store attribute data for one or more vertices. 
     
     
       9. The image generation system of  claim 1 , wherein the BVH comprises attribute data for the triangles. 
     
     
       10. The image generation system of  claim 1 , wherein the fetch shader is operable to obtain attribute data, and wherein the obtained attribute data is used to perform the vertex shading process. 
     
     
       11. An image generation method comprising:
 storing a bounding volume hierarchy, BVH, comprising a hierarchical structure of a plurality of triangles describing a virtual scene; 
 storing data for identifying the location of one or more triangles within the BVH; 
 identifying vertex indices for use in rendering images; 
 obtaining one or more triangles within the BVH corresponding to those vertex indices; and 
 providing vertex data corresponding to those triangles to a vertex shader operable to perform a vertex shading process, 
 wherein the respective locations of at least some of the plurality of triangles within the BVH are each indicated by a respective index and respective single bit value, which together identify all vertices of a respective one of the at least some of the plurality of triangles. 
 
     
     
       12. A non-transitory machine-readable storage medium which stores computer software which, when executed by a computer, causes the computer to perform a method comprising the steps of:
 storing a bounding volume hierarchy, BVH, comprising a hierarchical structure of a plurality of triangles describing a virtual scene; 
 storing data for identifying the location of one or more triangles within the BVH; 
 identifying vertex indices for use in rendering images; 
 obtaining one or more triangles within the BVH corresponding to those vertex indices; and 
 providing vertex data corresponding to those triangles to a vertex shader operable to perform a vertex shading process, 
 wherein the respective locations of at least some of the plurality of triangles within the BVH are each indicated by a respective index and respective single bit value, which together identify all vertices of a respective one of the at least some of the plurality of triangles.